Soft Pixel Art
There is no specific trigger word, just use "pixel art" or "pixel art style". Pretty much pixel perfect and should have minimal artifacts when downscaling 4X with nearest neighbor. I find downscaling with RotSprite 4X in Aseprite sometimes gives better results.
Check out my other model, Hard Edge Pixel Art, if you prefer sharp hard edges and a simpler style:
Hard Edge Pixel Art - v1.0 | Stable Diffusion LoRA | Civitai
Tip: Combine both of these LoRAs at 0.5 and 0.5 to get an in-between look!